Patent GB-184623-A (GB)
Title: Improvements in winches
IPC: B66D1/24
Filed: 1921-06-07
Abstract: 184,623. Mace, J. H. R. June 7, 1921. Gearing for stopping and starting machinery.- The multiple-disc friction clutches for the drums of winches of the type described in Specifications 23997/13 and 139,595, [both in Class 78 (v), Winding and paying-out apparatus &c.], are operated and controlled from a countershaft fitted with friction clutch and brake mechanism, the arrangement being such that the drum is locked whenever the controlling-handle is released. Fig. 1 shows one arrangement in which the screwed shaft 4 co-operates with a nut formed in the end of the drum to operate the disc. clutch 5 to connect the drum to or release it from the driving- shaft 2. The shaft 2 drives a loose clutch member 7 on the countershaft 1 through chain gearing 8, and the member 7 drives a second loose clutch member 11 in the reverse direction though a spur train. A sliding feathered clutch member 12 can be engaged alternatively with either of the members 7, 11 to drive the shaft 1 in either direction and correspondingly drive the screw shaft 4 through the chain 3. In the mid-position of the clutch member 12, a sliding conical disc brake 16 is applied to the shaft 1 by a spring. Movement of the member 12 in either direction, to engage one or other of the members 7, 11, simultaneously releases the brake through the medium of a rod 20 having a pushing and pulling action on the brake-lever 19. When it is desired to hoist, the corresponding clutch on the countershaft is engaged, and the shaft 4 is driven so that it moves axially to compress the plates of the clutch 5 until the drum takes up the full drive from the shaft 2 and from that time onward rotates in the same direction and at the same speed as the shaft 4. To stop the hoisting movement, the clutch member 12 is returned to midposition and the brake 16 re-applied, which, in effect, fixes the shaft 4. Meanwhile the continued driving of the drum in the hoisting direction results in the nut moving the shaft 4 axially to release the clutch sufficiently for the lead to commence running down. This reversal of the drum re-actuates the shaft 4 to re-engage the clutch to oppose, the fall by re-connecting the drum for hoisting. Between these two actions a state of balance is set up, as a result of which the drum remains stationary with the load suspended. To lower, the rotation of the shafts 1, 4 is reversed so that the shaft 4 is driven positively in the direction for releasing the clutch 5, and the lowering continues so long as the drum and the sha.ft 4 again rotate in the same direction at the same speed. If the load overruns, the excess rotation of the drum causes the re-engagement of the clutch to retard the fall. In some cases, instead of the spindle 4 co-operating with a nut formed in the end of the drum as illustrated, the spindle may be feathered and cooperate with a loose nut driven by a chain 3. Fig. 4 shows a modification in which a single drum clutch member 7 is employed in conjunction with a spring-controlled brake 16 and a nut 29 connected to, or released from, the drum by a disc clutch 30 normally applied by a spring 32. To raise the load the hand wheel 24, geared to a clutch lever, is manipulated to clutch up the member 7 and release the brake 16. Clearance 39 allows this movement to take place without affecting the nut clutch lever 35, so that the spring 32 remains operative to engage the clutch. The shaft 4 is thus moved axially through the held nut 29 as in the previous example. Disengaging the clutch 7 and re-applying the brake suspends the load as previously described. A further movement of the hand wheel in the same direction after disengaging the clutch 7 operates the lever 35 to release the nut clutch. The load then runs down, the drum moving relatively to the nut. Restoration of the controlling hand wheel re-applies the nut clutch and re-establishes control through the screwed shaft 4 as previously described. The hand wheel 24 may be omitted and the clutch lever actuated directly.